Find Out Everything You Need to Know About Heat Exchangers

January 26, 2017
By
Valley Heating, Cooling, Electrical

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When you discuss your HVAC system with a technician, it can help to have
a basic understanding of what the various parts do. When it comes to your
furnace, there's no more crucial part than the heat exchanger. That's
where most of the important work of producing heat occurs.

WHAT THE HEAT EXCHANGER DOES

Quite simply, a heat exchanger is a set of tubes — also referred
to as coils — looped through the furnace's air flow. The shape
of the coils differs, depending on the model of
furnace or the type of fuel your furnace uses.

Here's how it works: an igniter lights the burners in the combustion
chamber. The heat that is generated is pushed into the heat exchanger,
which becomes very hot. The furnace's blower motor blows air over
the heat exchanger and once the air is heated, it is pushed into the ductwork
and then distributed throughout the home.

Combustion gases that the burning fuel created are vented through a flue
in the roof, or through a wall.

WHEN HEAT EXCHANGERS CRACK

As you can imagine, the metal of the heat exchanger is subjected to considerable
stress as it heats up and cools, expanding and contracting. Over time,
small cracks can appear from which poisonous gases such as carbon monoxide
may leak. Depending on the size of the crack, it may be necessary to replace
the heat exchanger — which can be very expensive — or even
replace the furnace.

However, make sure you consult with a reputable HVAC contractor about cracks
in the heat exchanger, and do ask to see the cracks. Some signs indicating
you might have heat exchanger damage:

High levels of CO in the flue pipe

Burner flames should be steady and blue; if they are yellow/orange and
move around, the heat exchanger may be cracked.